Interest in the possibility that the consumption of coffee or caffeine might protect against the development of Alzheimer’s disease is growing. A retrospective Portuguese study of 54 cases of Alzheimer’s disease and 54 controls recently demonstrated that caffeine intake over the preceding 20 years was inversely and significantly associated with risk of Alzheimer’s disease.

Two large cross-sectional studies have examined the relationship

between the intake of coffee and tea and the prevalence of asthma.

A study of 72,284 Italians showed that there was an inverse

association between intake of coffee and prevalence of asthma.

Risk of asthma fell by 28% when three or more cups of coffee were

drunk every day.

Two studies, each on the Kaiser Permanente Medical Care

Program cohort in California, originally demonstrated that coffee

drinking might protect against liver cirrhosis. In the first study,

59 cases of liver cirrhosis were diagnosed and it was shown that

subjects who drank four or more cups of coffee per day had 80%

less chance of developing liver cirrhosis than non-coffee drinkers.

In the second study, it was reported that coffee drinkers had 23%

less chance of dying from liver cirrhosis than non-coffee drinkers.

A review of the scientific literature identified 8 case control

studies and 5 cohort studies on the relationship between coffee

consumption and risk of Parkinson’s disease which met the

criteria for inclusion in a meta-analysis. This analysis demonstrated

that coffee drinkers had 31% less chance of developing Parkinson’s

disease than non-coffee drinkers. Hence, the available evidence

consistently demonstrates that coffee consumption lowers the

risk of Parkinson’s disease.

In a subsequent cohort study of 45,289 men in the USA, 753 new cases of kidney stones were diagnosed and the risk of developing a stone fell by 10% in response to 240 ml/day of caffeinated or decaffeinated coffee. In a cohort study of 81,093 women in the USA, 719 new cases of kidney stones were identified and the risk of developing a stone fell by 10% in response to 240 ml caffeinated and 9% in response to 240 ml decaffeinated coffee. The available evidence consistently demonstrates that coffee consumption lowers the risk of developing a kidney stone.

In recent years studies have suggested that coffee drinking may be protective against the development of hepatocellular carcinoma independently of its aetiology. Coffee has been studied extensively in relation to other conditions affecting the liver and this is reported elsewhere on this site. In 2005 Japanese researchers (64) published their findings after conducting a large-scale population-based cohort study that confirmed a statistically significant inverse association between habitual coffee drinking and hepatocellular carcinoma.